Crown cap



Sept. 21, 1965 R. STUART 3,207,351

CROWN CAP Filed May 5, 1964 @xvwv QA@ '1mg 9 mvENToR.

United States Patent O Filed May 5, 1964, Ser. No. 365,040

15 Claims. (Cl. 21S-46) The present invention is a continuation-impartvof my copending application, Serial No. 352,619, filed March 17, 1964,and the entire disclosure in that application is by referenceincorporated herein.

This invention relates to improvements in crown caps of the type thatmay be removed from a container upon which the cap is mounted withoutthe use of an opening tool.

It is an object ofthe present invention to provide a crown cap havingtear tabs which may be manually grasped and by which the body of the capmay be torn ina plurality of places to break the hoop strength of thecap so that the cap may thereafter be readily removed from thecontainer.

It is a further object of the present invention to provide a crown capof the type stated in which the tabs are spaced circumferentially aboutthe skirt of the cap body, and wherein there is a generally linear zoneof weakness in the body that extends from each tab to an adjacent tab,which zone of weakness runs chord-wise across the crown of the cap sothat after tearing of the tabs,`one part of the cap body may be bentupwardly relative to another part of the body along the zone of weaknessto facilitate removal of the cap from the container.

It is a more specific object of the present invention to provide a crowncap of the type stated in which each chord-wise extending zone ofweakness is of variable weakness with the greater weakness being eitherat the periphery of the crown or at the central part of the crown. Ifthe weaker part of the zone is at the periphery of the crown and thestronger part is at the central part of the crown, the crown hasimproved strength at its central part to inhibit bulging of the crownthereat when the interior of the container is under pressure, as forinstance, when the container is filled with a carbonated beverage.Conversely, if the weaker part of the zone is at the central part of thecrown, some sacrifice of the strength of the central part of the crownis made,but at the same time,

it is easier t-o bend the cap'around the zone of weakness. In accordancewith the principles of the present invention, the variation in weaknessin the zones of weakness may be accomplished by forming in the crown achordal score line of a depth which varies from a minimum or leven zeroat one end of the chord to a maximum at the other end of the crown. Thezone of weakness may also be formed by a score line extending from theperiphery of the crown inwardly thereof for only a short distance or byscoring a part of the crown such that the ends of the score line stopshort of the periphery.

The attainment of the above and vfurther objects of the presentinvention will be apparent from the following specification taken inconjunction with the accompanying drawing forming a part thereof.

In the drawing;

FIG. 1 is a top plan view of a crown cap constructed in accordance withand embodying the present invention;

FIG. 2 is a perspective view of the crown cap shown mounted on acontainer;

FIG. 3 is a fragmentary side elevational view on an enlarged scale ofthe cap and container shown in FIG. 2;

FIG. 4 is `a fragmentary sectional view taken along line 4-4 of FIG. 3;

FIG. 5 is a fragmentary sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a fragmentary sectional view similar to FIG.

3,207,351 Patented Sept. 2l, 1965 ICS 5 but showing a modified form ofthe present invention;

FIG. 7 is a perspective view of another modified form of cap shownmounted upon a container;

FIG. 8 is a fragmentary sectional view taken along line 8-8 of FIG. 7;and

FIGS. 9 and l0 are sectional views similar to FIG. 8 and showing twoadditional modified forms of the present invention.

Referring now in more detail to the drawing, 1 designates a crown capthat comprises a body 3 of metal, such as aluminum, tinplate, blackplateor the like, having a circular top or crown 5 and an annular skirt 7that depends from the periphery of the crown 5 and terminates in a rimor free end 9. The bottom portion 13 of the skirt 7 is outwardlydirected and generally conical while the upper portion 15 of the skirtis generally cylindrical. The skirt 7 is corrugated by circumferentiallyspaced flutes 17 that extend from the free end 9 upwardly toward thecrown 5. The utes 17 extend across the lower porcurved juncture of theskirt 7 and crown 5. The end portions 25, 27 of each slit define thesides of a tab 21, and the end portions 25, 27 terminate at spacedpoints above the free end 9 of the skirt 7, thereby to leave bridges 29,31 of solid metal between the terminals of the end portions 25, 27 andthe free end 9 of the skirt. The end portion 25 terminates closer to thefree end 9 than does the end portion 27 whereby the bridge 29 is shorterthan the bridge 31, and for purposes presently more fully appearing. Theend portions 25, 27 may lie along the ridges of two adjacent flutes, orwhere a wider tab is desired, may lie along two alternate utcs so that aute lies between the end portions 25, 27.

Formed in the body and extending across the crown 5 from each tab 21 toan adjacent tab, are three generally linear zones of weakness 33, 33,33. In the form of the invention shown in FIGS. l-5, each zone ofweakness 33 comprises a score line 35 that extends chord-wise across thecrown 5. The three score lines 35, 35, 35 intersect to form anequi-lateral triangle with the apices 37, 37, 37 of the triangle lyingin the crown or approximately in the curved region of the juncture ofthe skirt 7 and crown 5L A line of weakness in the body 3, such as ascore line 39, extends from each apex 37 downwardly along the upperportion 15 of the skirt 7 to approximately the middle of the slit 19 ofthe adjacent tab 21. In the drawing, the widths of the score lines areshown exaggerated for purposes of clarity of illustration.

Each score line 35 is of variable depth so that each zone 33 is ofvariable weakness across the crown. As shown in FIG. 5, the depth of thescore line 33 is a maximum at each apex 37 and tapers to a minimum depthat 41 midway between the two apices 37, 37. The score line 39 may have adepth which is approximately the same as that at the apex 37. By way ofexample but not of limitation, the maximum depth of the score line 33may be about three fourths the depth of the metal, and the minimum depthmay be about one half the depth of the metal. Accordingly, crown 5 hasgreater strength in its central portion than at its periphery.

FIGURE 6 shows a modified zone of weakness in a cap which is otherwiseidentical to the cap previously described. However, in a cap of the typeshown in FIG. 6,

Conventionally the cap has twenty one l the depth of each score line 43,y44 diminishes to zero at the midpoint 41 of the chord so that, ineffect, the score lines are short Vs extending from each apex 37.

FIGS.,7 and 8 show a further modified form of cap which is identical tothe cap of FIGS. lexcept as to the construction of the zone of weakness33a. In FIG- URES 7 and 8, score lines 45, 47 form a V extending fromeach apex 37 into the crown. Each score line 45 is in alignment with thescore line 47 running from the adjacent apex 37. As best seen in FIG. 8,the score lines v45, 47 are of uniform depth for substantially the fullllength of each, and with each score line 45, 47 extending approximatelyone third the distance between apices 37, 37 so as to leave in the crownan unscored region 49 in the zone of weakness 33a between the adjacentterminals 51, 53 of the score lines 45, 47. The depths of the scorelines 45, 47 may, however, taper from the apices to a lesser depth attheir terminals 51, 53 or the depths may taper to zero at the terminals51, 53.

FIGS. 9 and 10 show zones of variable weakness extending between tabs 21in which each zone is weaker -at the central part of the crown 5 than atthe periphery thereof, to enhance the ease of bending the cap about thezone of weakness 33b after tearing the tabs 21, as will presently bemore fully described. In FIG. 9 a score line lies approximately midwaybetween two apices 37 with the ends of the score line terminating inspaced relation to the apices 37. The score line 61 may have anysuitable depth that is the same or greater than the depth of score atthe apices 37, 37 of the-zones of weakness 33b. These apices 37, 37, 37are, however, in this form of the invention merely the upper ends of thescore lines 39, 39, 39.

In FIG. l0 the cap has a zone of weakness 33e that i is defined by ascore line 63 that extends between apices 37, 37 and has a depth thatincreases from a maximum at the center 65 of the score line to a minimumat the apices 37, 37. By way of example but not of limitation, the depthof the score line 63 may be about three fourths the thickness of themetal as a maximum and about one half the depth of the metal as aminimum.

Thev cap 1 has a conventional flexible, gas impervious yielding sealingliner underlying the crown 5 of a diameter approximately that of theinternal diameter of the skirt at the crown. The liner 55 may be of corkWithan impermeable plastic disc adhesively secured to the undersidethereof and held onto the cap in any standard manner. Alternatively, theliner 55 may be a vinyl plastisolof the type disclosed in U.S. Patent2,937,404.

The cap 1 may be mounted on the container 57 by conventional high speedcapping machinery. During the capping operation, the skirt 7 is radiallyoutwardly flexed to snap over the container bead S9 and then moves underits natural resiliency, or is mechanically moved, radially inwardly intogripping engagementwith the underside of the container bead 59 to holdthe cap onto the container bead 59 by the hoop strength of the distendedcap skirt. A gap 61 is formed between the upper end 23 of the tab 21 andthe part of the skirt therebehind. The portions of the skirt between theflutes 17 engage the bottle bead, and the gripping of the container atthe skirt also presses the sealing liner 55 downwardly into firm sealingengagement with the top of the container bead 59.

When it is desired to remove the cap 1 from the con- -tainer bead 59,the tear tabs 21 are grasped by inserting the linger-nail behind theupper ends 23 of the tabs, as at gaps 61, whereupon the tabs are pulledoutwardly and downwardly. This tears one or more of the bridges 29, 31of metal adjacent to each of the respective tabs 21 and thereby breaksthe hoop strength of the skirt. Since the bridge 29 is shorter than thebridge 31, tearing of the bridge 29 is more easily effected, and thereis a great likelihood that only the region 29 will be completely torn,leaving the tab attached to the skirt ut the region 31. The cap 1 maythen be removed from the container bead 59, and to facilitate suchremoval, a part of the body may be bent upwardly along one or more ofthe zones of weakness 33, or 33a, 33b, or 33C, as the case may be.

While I have herein illustrated three tabs equally spaced about the capbody with three zones of weakness extending across the cap, a greater orlesser number of tabs may be used. For example, if four tabs are used,the four zones of weakness will intersect at apices and lform aquadrilateral. If two tabs are used, they may be spaced degrees apartwith a single zone of weakness extending between them and across thecrown 5. Moreover, where more than two tear tabs are used they need notbe equally spaced about the cap body but no two adjacent tabs should bemore than about 180 degrees apart.

In compliance with the requirements of the patent statutes, I haveherein shown and described a preferred embodiment of the presentinvention. It is, however, to be understood that the invention is notlimited to the precise construction herein shown, the same being merelyillustrative of the principles of the invention. What is new andconsidered to be secured by Letters Patent is:

1. A crown cap comprising a body having a crown and a peripheral skirtsurrounding and projecting away from the crown and adapted for grippingengagement with a container neck to retain the cap thereon, tear tabs onthe body to facilitate removal of the cap from the container neck, saidtabs being circumferentially spaced about the body and each beingdefined by a line of weakness with the end portions of the line deningthe sides of the tab and terminating at spaced points adjacent to butspaced from the free end of the skirt and extending from there towardthe crown, and means forming a zone of weakness in the body extendingsubstantially from each tab to an adjacent tab and through the crown,each zone being of variable weakness and constituting a line about whichthe body may be folded after tearing of the body by the tear tabs andwith at least part of each line of fold being formed by a score in thecrown.

2. A crown cap according to claim 1 in which the depth of the scorevaries from the part of the zone remote from the tabs to the parts ofthe body adjacent to the tabs.

3. A crown cap according to claim 1 in which the zone of weaknessincludes an unscorcd region in the crown.

4. A crown cap according to claim 1 in which the zone is of greaterweakness adjacent to the tabs and is of lesser weakness in the crownremote from each tab.

'5. A crown cap comprising a body having a crown and a peripheral skirtsurrounding and projecting away from the crown and adapted for grippingengagement with a container neck to retain the cap thereon, at leastthree tear tabs on the body to facilitate removal of the cap from thecontainer neck, said tabs being circumferentially spaced about the bodyand each being defined hy a line of-weakness Iwith the end portions ofthe line defining the sides of the -tab and terminating at spaced pointsadjacent to but spaced from the free end of the skirt and extending fromthere toward the crown, and means forming a zone of weakness in the.body extending substantially from each tab to each adjacent tab andthrough the crown, the zones intersecting to deline a polygon havingapices respectively adjacent to each talb, each zone being of variableweakness and constituting a line about which the body may be foldedafter tearing of the tear tabs, and a line of weakness in the 'bodyextending from eac-h apex to the adjacent tab.

6. A crown cap according to claim 5 in which at least one of the zonesof Weakness is formed 'by a score line extending between two apices, thedepth of the score varying from each apex toward the part of said zoneap proximnlcly midway between the two apices.

7. A crown cup according to claim S in which n zone 5 of weaknessincludes a score line in the crown and an unscored region in the crown.

8. A crown cap according to claim in which the zone of weakness includesa score line between the apices and an unscored part of the crownbetween the ends of the score line and the adjacent apices.

9. A crown cap comprising a body having a crown and a peripheral skirtsurrounding and projecting away from the crown and adapted forgrippingengagement with a container neck to retainthe cap thereon, teartabs on the body to' facilitate removal of the cap from the containerneck, said tabs being circumferentially spaced about `the body and eachbeing defined by a line of weakness with the end |portions of the linedefining'the sides of the tab and terminating at spaced points adjacentto but spaced from the free end of the skirt and extending from theretoward the crown and with an intermediate portion of the line definingan end of the tab that is within the skirt, a line of weakness extendingfrom each said end of the tab and terminating in the crown, and a zoneof weakness extending over the crown from t-he crownterminal of each ofsaid .last mentioned score lines to the crown-terminal of an adjacentscore line and constituting a generally linear zone about which the capmay be folded to 'facilitate removal of lthe cap lfrom the containerafter tearin'g of the tear tabs, each zone of weakness including atleast one score line and being of variable weakness with the greaterweakness being at said crown terminals and a lesser weaknessintermediate said cro-wn terminals.

10. A crown cap according to claim 9 in which the score line intersectstwo of said crown terminals and is of progressively decreasing depth ina direction away from eac-h said crown terminal.

' 1'1. A crown cap Iaccording to claim 9 in which there is a score lineextending from each of the crown terminals toward another crown terminaland ending in spaced relation to each other.

. 12. A crown cap comprising a body having a crown and a peripheralskirt surrounding and projecting away from the crown and adapted forgripping engagement with a container neck to retain the cap thereon,tear tabs `on the body to rfacilitate removal of the cap from thecontainer neck, said tabs being-circumferentially spaced about the bodyand each being defined by a line of weakness with the end portions ofthe line defining the sides ot the tab and terminating at spaced pointsadjacent to but spaced from the free end of the skirt and extending fromthere toward the crown, and means forming a zone of weakness in the body'between two tabs and about which one part of the body may be bentrelative to the other after tearing of the skirt by the tear tabs, saidzone of weakness including a score line extending chordwise across thecrown and Vbeing of variable depth with the depth of the score being amaximum at the ends of the chord and being a minimum substantially atthe middle of the chord.

13. A crown cap comprising a body having a crown and a peripheral skirtsurrounding and projecting away from the crown and adapted for grippingengagement with a container neck to retain the cap thereon, tear tabs onthe ibody to facilitate removal of the ca'p from the container neck,said tabs being circumferentially spaced about the body and each beingdefined by a line of weakness with the end portions 0f the line definingthe sides of the tab and terminating at spaced points adjacent to butspaced from the free end of the skirt and extending from there towardthe crown, and means forming a zone of weakness in the body between twoadjacent tabs and about which one part of the body may be bent relativeto the other after tearing of the skirt by the tear tabs, said Zone ofweakness extending chord-wise across the crown and including two alignedscore lines extending from the periphery of the crown toward each otherand terminating at spaced points within the crown and leaving the partof the crown therebetween Unscored.

.14. A crown cap comprising a body having a crown and a peripheral skirtsurrounding and projecting away from the crown and adapted for grippingengagement with a container neck to retain the cap thereon, tear. tabson the body to facilitate removal ofthe cap from the container neck,said tabs being circtunferentially spaced about the body and each beingdefined by a line of weakness with end portions of the line defining thesides of the tab and terminating at spaced points adjacent to but spacedfrom the free end of the skirt and extending from there toward thecrown, and means forming a zone of weakness between two tabs andconstituting a line about which one part of the lbody may be bentrelative to the other after tearing of the skirt by the tabs, said zonebeing of variable weakness with the greater weakness being in the partof the zone remote from the tabs and the lesser weakness ibeing in thepart of the zone adjacent to the tabs.

15. A crown cap according to claim 14 in which the zone of weakness isformed by a score line the depth of which progressively increases from alesser depth adjacent to each tab to a greater depth in the part of zoneVremote from the tabs.

References Cited by the Examiner UNITED STATES PATENTS kFRANKLIN T.GARRETT, Primary Examiner.

1. A CROWN CAP COMPRISING A BODY HAVING A CROWN AND A PERIPHERAL SKIRTSURROUNDING AND PROJECTING AWAY FROM THE CROWN AND ADAPTED FOR GRIPPINGENGAGEMENT WITH A CONTAINER NECK TO RETAIN THE CAP THEREON, TEAR TABS ONTHE BODY TO FACILITATE REMOVAL OF THE CAP FROM THE CONTAINER NECK, SAIDTABS BEING CIRCUMFERENTIALLY SPACED ABOUT THE BODY AND EACH BEINGDEFINED BY A LINE OF WEAKNESS WITH THE END PORTIONS FOR THE LINEDEFINING THE SIDES OF THE TAB AND TERMINATING AT SPACED POINTS ADJACENTTO BUT SPACED FROM THE FREE END OF THE SKIRT AND EXTENDING FROM THREETOWARD THE CROWN, AND MEANS FORMING A ZONE OF WEAKNESS IN THE BODYEXTENDING SUBSTANTIALLY FROM SAID TAB TO AN ADJACENT TAB AND THROUGH THECROWN, EACH ZONE BEING OF VARIABLE WEAKNESS AND CONSTITUTING A LINEABOUT WHICH THE BODY MAY BE FOLDED AFTER TEARING OF THE BODY BY THE TEARTABS AND WITH AT LEAST PART OF EACH LINE OF FOLD BEING FORMED BY A SOCREIN THE CROWN.